/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.solr.util.tracing;

import io.opentelemetry.context.propagation.TextMapGetter;
import jakarta.servlet.http.HttpServletRequest;
import java.util.Iterator;

/**
 * {@code HttpServletRequest} aware {@code TextMapGetter} that allows header data to be extracted
 * from a request
 */
public class HttpServletRequestGetter implements TextMapGetter<HttpServletRequest> {

  @Override
  public Iterable<String> keys(HttpServletRequest carrier) {
    return new Iterable<String>() {
      @Override
      public Iterator<String> iterator() {
        return carrier.getHeaderNames().asIterator();
      }
    };
  }

  @Override
  public String get(HttpServletRequest carrier, String key) {
    if (carrier == null) {
      return null;
    }
    return carrier.getHeader(key);
  }
}
